Originally designed to go against the formidable Siegfried Line in Europe, the first prototype was not completed until December of 1945, too late to see in combat. Powered by the same Ford GAF V-8 gasoline engine used by the M26 Medium Tank, this vehicle was so heavy that the transmission and final drive had to be geared down to a top speed of 8 miles per hour. Double tracks were necessary to prevent it from sinking into the ground on cross-country treks, but the outside track assemblies on each side could be removed to allow transport by truck or rail. The frontal armor is 12” thick, with an 11.5” on the gun mantlet, which protected the 105mm canon. The side armor over the tracks is 4” thick. Only two of these monsters were ever completed, with this prototype (Pilot Vehicle #1) being the only survivor.

U.S. Marines with Company A, 4th Tank Battalion, Task Force Mech (TF Mech), Multi-National Force - West (MNF-W), Ground Combat Element (GCE), wait in their M1A1 Abrams tank before firing their main gun in the Jazeerah Desert, Iraq on June 26, 2008. TF Mech is conducting disruption operations in part of Operation Defeat al Qaeda in the North (Op DAN) to deny enemy sanctuary and prevent foreign fighter entry into the area.

Heavy Equipment Transporters (HET's) are capable of carrying a 70-ton Main Battle Tank on board. They can move their load rapidly and cost-effectively, saving wear and tear on the tracks – and the roads. The semi-trailers are equipped with a heavy-duty winch – giving an all-up weight of 104 tons.

The new Heavy Equipment Transporter is the most powerful tank transporter in production. It consists of an Oshkosh 1070F 8x8 tractor truck and a King Trailer GTS 100 seven axle semi-trailer.

The fully integrated power pack, comprises of a Caterpillar C18 after-cooled, turbocharged diesel engine developing 700hp, and is linked through to an electronically controlled X300 transmission unit.

In 1957, it was determined that the Soviets were in the process of developing a new medium tank, the T-62, with a 115 mm gun, superior to that of the American M48 tank. In response, an M48 tank was fitted with a new engine and later with a variant of the British 105 mm L7 series gun. This new vehicle (originally designated M68) was put into production in 1959, reclassified as the M60 and entered service in 1960. Over 15,000 M60s were constructed.